Portion of a display screen with an icon



The FIGURE is a front view of the portion of a display screen with an icon showing the new design.

The broken lines depict environmental subject matter only and form no part of the claimed design.

The dot-chain lines depict a boundary between an unclaimed and a claimed surface and form no part of the claimed design. 

The ornamental design for an portion of a display screen with an icon, as shown and described. 